HVAC Duct

ABSTRACT

An HVAC airflow duct has a polymeric material that meets UL723 and/or ASTM E84 of at least 25/50 or better and/or maintains or exceeds a minimum insulation value.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/757,033, filed on Jan. 25, 2013 by Richard LeeJameson, entitled “Foam Duct Panel,” which is incorporated by referenceherein as if reproduced in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Some heating, ventilation, and/or air conditioning (HVAC) systemscomprise cabinets and/or ducts configured to receive airflowtherethrough. In some cases, a component of a cabinet and/or duct maycomprise fibrous insulation material, materials comprising heat transferconductivities that allow condensation formation on the component,and/or extraneous layers of material that, together with foam, areconfigured to provide a composite component. Some HVAC air handlingunits and/or are associated with potential sources of fire.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description, wherein like reference numerals represent likeparts.

FIG. 1 is an oblique view of an air handling unit according toembodiments of the disclosure;

FIG. 2 is an orthogonal view of the front of the air handling unit ofFIG. 1;

FIG. 3 is a partially exploded oblique view of the air handling unit ofFIG. 1;

FIG. 4 is a simplified oblique view of the air handling unit of FIG. 1showing a plurality of inner shell components encased within outerskins;

FIG. 5 is an oblique left side view of the heat exchanger cabinet rightshell of FIG. 1;

FIG. 6 is an oblique left side view of the blower cabinet right shell ofFIG. 1;

FIG. 7 is an oblique front view of a panel of the air handling unit ofFIG. 1;

FIG. 8 is an oblique rear view of a panel of the air handling unit ofFIG. 1;

FIG. 9 is an oblique front view of an alternative embodiment of a panel;

FIG. 10 is an orthogonal rear view of the panel of FIG. 9;

FIG. 11 is an oblique front cut-away view of a gas furnace according toembodiments of the disclosure;

FIG. 12 is a schematic view of a structure associated with an HVACsystem according to an embodiment of the disclosure;

FIG. 13 is an orthogonal side view of a panel comprising an attachedhook;

FIG. 14 is an orthogonal side view of a panel comprising a hook that isintegral with a skin of the panel; and

FIG. 15 is an orthogonal side view of a panel with an integral hook.

DETAILED DESCRIPTION

This disclosure provides, in some embodiments, systems and methods for(1) forming an HVAC air handling unit, an HVAC cabinet, and/or an HVACduct comprising a substantially polyetherimide based foam, (2) providinga relatively high heat resistant, highly insulative, and/or structurallyrigid HVAC air handling unit, HVAC cabinet, and/or HVAC duct comprisinga polyetherimide based foam, and (3) sealing an HVAC air handling unit,an HVAC cabinet, and/or an HVAC duct using a panel comprising apolyetherimide based foam. In some embodiments, an inner wall of an HVACair handling unit, an HVAC cabinet, and/or an HVAC duct that may beexposed to an airflow may comprise a foamed and/or unfoamed polymericmaterial that meets UL723 and/or ASTM E84 of at least 25/50 or betterand/or maintains or exceeds a minimum insulation value for a givenapplication, in some cases, an R Value of about 4.2 or greater, such as,but not limited to, polyetherimide.

Referring now to FIGS. 1-3, an air handling unit (AHU) 100 according tothe disclosure is shown. In this embodiment, AHU 100 comprises a lowerblower cabinet 102 attached to an upper heat exchanger cabinet 104. Mostgenerally and for purposes of this discussion, AHU 100 may be describedas comprising a top side 106, a bottom side 108, a front side 110, aback side 112, a left side 114, and a right side 116. Such directionaldescriptions are meant to assist the reader in understanding thephysical orientation of the various components parts of the AHU 100 butthat such directional descriptions shall not be interpreted aslimitations to the possible installation orientations of an AHU 100.Further, the above-listed directional descriptions may be shown and/orlabeled in the figures by attachment to various component parts of theAHU 100. Attachment of directional descriptions at different locationsor two different components of AHU 100 shall not be interpreted asindicating absolute locations of directional limits of the AHU 100, butrather, that a plurality of shown and/or labeled directionaldescriptions in a single Figure shall provide general directionalorientation to the reader so that directionality may be easily followedamongst various the figures. Still further, the component parts and/orassemblies of the AHU 100 may be described below as generally havingtop, bottom, front, back, left, and right sides which should beunderstood as being consistent in orientation with the top side 106,bottom side 108, front side 110, back side 112, left side 114, and rightside 116 of the AHU 100.

Blower cabinet 102 comprises a four-walled fluid duct that accepts fluid(air) in through an open bottom side of the blower cabinet 102 andallows exit of fluid through an open top side of the blower cabinet 102.In this embodiment, the exterior of the blower cabinet 102 comprises ablower cabinet outer skin 118 and a blower cabinet panel 120. The blowercabinet panel 120 is removable from the remainder of the blower cabinet102 thereby allowing access to an interior of the blower cabinet 102.Similarly, heat exchanger cabinet 104 comprises a four-walled fluid ductthat accepts fluid (air) from the blower cabinet 102 and passes thefluid from an open bottom side of the heat exchanger cabinet 104 andallows exit of the fluid through an open top side of the heat exchangercabinet 104. In this embodiment, the exterior of the heat exchangercabinet 104 comprises a heat exchanger cabinet outer skin 122 and a heatexchanger cabinet panel 124. The heat exchanger cabinet panel 124 isremovable from the remainder of the heat exchanger cabinet 104 therebyallowing access to an interior of the heat exchanger cabinet 104.

The AHU 100 further comprises a plurality of selectively removablecomponents. More specifically, the AHU 100 comprises a heater assembly126 and may be removably carried within the heat exchanger cabinet 104.The AHU 100 further comprises a refrigeration coil assembly 128 that mayalso be removably carried within the heat exchanger cabinet 104. In thisembodiment, the heater assembly 126 is configured to be optionallycarried within heat exchanger cabinet 104 nearer the top side 106 of theAHU 100 than the refrigeration coil assembly 128. Similarly, the AHU 100comprises a blower assembly 130 that may be removably carried within theblower cabinet 102. The AHU 100 may be considered fully assembled whenthe blower assembly 130 is carried within the blower cabinet 102, eachof the refrigeration coil assembly 128 and the heater assembly 126 arecarried within the heat exchanger cabinet 104, and when the blowercabinet panel 120 and heat exchanger cabinet panel 124 are suitablyassociated with the blower cabinet outer skin 118 and the heat exchangercabinet outer skin 122, respectively. When the AHU 100 is fullyassembled, fluid (air) may generally follow a path through the AHU 100along which the fluid enters through the bottom side 108 of the AHU 100,successively encounters the blower assembly 130, the refrigeration coilassembly 128, and the heater assembly 126, and thereafter exits the AHU100 through the top side 106 of the AHU 100.

In this embodiment, each of the four walls of the blower cabinet 102 andthe heat exchanger cabinet 104 are configured to have a double-wallconstruction. More specifically, the heat exchanger cabinet 104 furthercomprises a heat exchanger cabinet right shell 132 and a heat exchangercabinet left shell 134. In this embodiment, the heat exchanger cabinetright shell 132 and the heat exchanger cabinet left shell 134 may bejoined to generally form the interior of the heat exchanger cabinet 104.In order to form the above-mentioned double-wall construction for theheat exchanger cabinet 104, the heat exchanger cabinet outer skin 122generally covers the right side and back side of the heat exchangercabinet right shell 132 while also generally covering the left side andback side of the heat exchanger cabinet left shell 134. Most generally,the heat exchanger cabinet right shell 132, the heat exchanger cabinetleft shell 134, and the heat exchanger cabinet outer skin 122 are shapedso that upon their assembly together a heat exchanger cabinet wall spaceexists between the heat exchanger cabinet outer skin 122 and each of theheat exchanger cabinet right shell 132 and the heat exchanger cabinetleft shell 134. The blower cabinet right shell 136, the blower cabinetleft shell 138, and the blower cabinet outer skin 118 are also shaped sothat upon their assembly together a blower cabinet wall space existsbetween the blower cabinet outer skin 118 and each of the blower cabinetright shell 136 and the blower cabinet left shell 138.

In some embodiments, one or more of the heat exchanger cabinet wallspace and blower cabinet wall space may be at least partially filledwith a foamed and/or unfoamed polymeric material that meets UL723 and/orASTM E84 of at least 25/50 or better and/or maintains or exceeds aminimum insulation value for a given application, in some cases, an RValue of about 4.2 or greater, such as, but not limited to,polyetherimide. At least partially filling one or more of the spaces mayincrease a structural integrity of the AHU 100, may increase a thermalresistance of the AHU 100 between the interior of the AHU 100 and theexterior of the AHU 100, may decrease air leakage from the AHU 100, andmay reduce and/or eliminate the introduction of volatile organiccompounds (VOCs) into breathing air attributable to the AHU 100. Such areduction in VOC emission by the AHU 100 may be attributable to the lackof and/or reduced use of traditional fiberglass insulation within theAHU 100 made possible by the insulative properties provided by thefoamed and/or unfoamed polymeric material that meets UL723 and/or ASTME84 of at least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide, thatmay be disposed within the spaces.

In some embodiments, each of the blower cabinet outer skin 118 and theheat exchanger cabinet outer skin 122 may be constructed of metal and/orplastic. Each of the heat exchanger cabinet right shell 132, the heatexchanger cabinet left shell 134, blower cabinet right shell 136, andblower cabinet left shell 138 may be constructed of a sheet moldingcompound (SMC). The SMC may be chosen for its ability to meet theprimary requirements of equipment and/or safety certificationorganizations and/or its relatively rigid cleanable surfaces that areresistant to mold growth and compatible with the use of antimicrobialcleaners. In some embodiments, polyurethane foam may be used to fill thespaces and the polyurethane foam may comprise refrigerant and/or pentaneto enhance the thermal insulating characteristics of the foam. Ofcourse, in alternative embodiments, any other suitable material may beused to form the components of the AHU 100. In still other embodiments,the above-described shells and skins may comprise the foamed and/orunfoamed polymeric material that meets UL723 and/or ASTM E84 of at least25/50 or better and/or maintains or exceeds a minimum insulation valuefor a given application, in some cases, an R Value of about 4.2 orgreater, such as, but not limited to, polyetherimide. Further, theshells and/or skins may be formed integrally with the above-describedthe foamed and/or unfoamed polymeric material that meets UL723 and/orASTM E84 of at least 25/50 or better and/or maintains or exceeds aminimum insulation value for a given application, in some cases, an RValue of about 4.2 or greater, such as, but not limited to,polyetherimide, that fills the above-described spaces so that theshell/skin/space combinations may each comprise substantially unitarycomponents of substantially homogenous material construction. It will beappreciated that the panel 124 may be constructed in any of theabove-described manners and particularly may comprise the foamed and/orunfoamed polymeric material that meets UL723 and/or ASTM E84 of at least25/50 or better and/or maintains or exceeds a minimum insulation valuefor a given application, in some cases, an R Value of about 4.2 orgreater, such as, but not limited to, polyetherimide.

Further, each of the heat exchanger cabinet right shell 132 and the heatexchanger cabinet left shell 134 comprise an interior side surface 146,an interior rear surface 148, an exterior side surface, and an exteriorrear surface. Similarly, each of the blower cabinet right shell 136 andthe blower cabinet left shell 138 comprise an interior side surface 154,an interior rear surface 156, an exterior side surface, and an exteriorrear surface. Most generally, and with a few exceptions, each of thepairs of interior side surfaces 146, interior rear surfaces 148,exterior side surfaces, exterior rear surfaces, interior side surfaces154, interior rear surfaces 156, exterior side surfaces, and exteriorrear surfaces are substantially mirror images of each other. Morespecifically, the above listed pairs of surfaces are substantiallymirror images of each other about a bisection plane 162 (see FIG. 2)that is generally parallel to both the AHU left side 114 and the AHUright side 116 and which is substantially equidistant from both the AHUleft side 114 and the AHU right side 116.

Referring now to FIGS. 4 and 5, simplified views of the AHU 100 areprovided. Each of the heat exchanger cabinet right shell 132, the heatexchanger cabinet left shell 134, the blower cabinet right shell 136,and the blower cabinet left shell 138 comprise integral features forcarrying removable components of the AHU 100. More specifically, theinterior side surfaces 146 and interior rear surfaces 148 of the heatexchanger cabinet right shell 132 and the heat exchanger cabinet leftshell 134 comprise heater assembly mounting channels 200 bound above andbelow by heater assembly rails 202. The heater assembly rails 202protrude inwardly from the remainder of the respective interior sidesurfaces 146 and interior rear surfaces 148 so that complementary shapedstructures of the heater assembly 126 may be received within thechannels 200 and retained within the channels 200 by the heater assemblyrails 202. In this embodiment, the heater assembly 126 may beselectively inserted into the heat exchanger cabinet 104 by aligning theheater assembly 126 properly with the heater assembly mounting channels200 and sliding the heater assembly 126 toward the AHU back side 112. Ofcourse, the heater assembly 126 may be selectively removed from the heatexchanger cabinet 104 by sliding the heater assembly 126 away from theAHU back side 112. Further, one or more of the interior side surfaces146 may comprise a heater assembly shelf 204 to slidingly receive aportion of the heater assembly 126 during insertion of the heaterassembly 126 until the heater assembly 126 abuts a shelf back wall 206.

Still referring to FIGS. 4 and 5, the interior side surfaces 146 of theheat exchanger cabinet right shell 132 and the heat exchanger cabinetleft shell 134 comprise refrigeration coil assembly mounting channels208 bound above and below by refrigeration coil assembly rails 210. Therefrigeration coil assembly rails 210 protrude inwardly from theremainder of the respective interior side surfaces 146 so thatcomplementary shaped structures of the refrigeration coil assembly 128may be received within the channels 208 and retained within the channels208 by the refrigeration coil assembly rails 210. In this embodiment,the refrigeration coil assembly 128 may be selectively inserted into theheat exchanger cabinet 104 by aligning the refrigeration coil assembly128 properly with the refrigeration coil assembly mounting channels 208and sliding the refrigeration coil assembly 128 toward the AHU back side112. Of course, the refrigeration coil assembly 128 may be selectivelyremoved from the heat exchanger cabinet 104 by sliding the refrigerationcoil assembly 128 away from the AHU back side 112.

It will further be appreciated that one or more of the heat exchangercabinet right shell 132 and the heat exchanger cabinet left shell 134may comprise integrally formed electrical conduit apertures 212 whichform openings between the interior of the heat exchanger cabinet 104 andthe heat exchanger cabinet wall space. The electrical conduit apertures212 are formed and/or shaped to closely conform to the shape ofelectrical lines and/or electrical conduit that may be passed throughthe electrical conduit apertures 212. However, in some embodiments,stabilizer pads 214 may be integrally formed about the circumference ofthe electrical conduit apertures 212 so that the electrical lines and/orelectrical conduit may be more tightly held, isolated from the generalcylindrical surface of the electrical conduit apertures 212, and/or toreduce friction of insertion of electrical lines and/or electricalconduit while retaining a tight fit between the stabilizer pads 214 andthe electrical lines and/or electrical conduit. Further, the stabilizerpads 214 may be configured to interact with nuts of electrical conduitconnectors so that the stabilizer pads 214 serve to restrict rotationalmovement of such nuts. By restricting such rotational movement of nuts,the stabilizer pads 214 may provide easier assembly and/or disassemblyof the electrical conduit and related connectors to the heat exchangercabinet 104. The electrical conduit apertures 212 are not simply holesformed in the interior side surfaces 146, but rather, are substantiallytubular protrusions extending outward from the exterior side surfaces.

It will further be appreciated that one or more of the heat exchangercabinet right shell 132 and the heat exchanger cabinet left shell 134may comprise drain pan indentions 216. More specifically, the heatexchanger interior side surfaces 146 may generally comprise a slopedportion 218 sloped from a bottom side to the drain pan indentions 216 sothat the bottom of the interior side surfaces 146 protrude furtherinward and the remainder of the sloped portion 218. The drain panindentions 216 may form a concavity open toward the interior of the heatexchanger cabinet 104. The interior side surfaces 146 further comprisesa front boundary wall 220 with integral drain tubes 222 extending intothe concavity formed by the drain pan indentions 216. In someembodiments, the AHU 100 may be installed and/or operated in aninstallation orientation where the drain pan indention 216 of aninterior side surface 146 is located below the refrigeration coilassembly 128 and so that fluids may, with the assistance of gravity,aggregate within the concavity of the drain pan indention 216 andthereafter exit the AHU 100 through the integral drain tubes 222. Morespecifically, the sloped portion 218 may direct fluids falling from therefrigeration coil assembly 128 toward the concavity formed by a drainpan indention 216. In this manner, the integrally formed slope portion218, the drain pan indentions 216, and the front boundary wall 220 mayserve as a condensation drain pan for the AHU 100 and may prevent theneed to install a separate drain pan and/or to rearrange theconfiguration of a separate drain pan based on a chosen installationorientation for the AHU 100. Further, when in use, a drain pan indention216 and sloped portion 218 may cooperate with airflow generated byblower assembly 130 to direct condensation to the integral drain tubes222.

It will further be appreciated that one or more of the heat exchangercabinet right shell 132 and the heat exchanger cabinet left shell 134may comprise integral assembly recesses 224. Assembly recesses 224 maybe located near a lower end of the heat exchanger cabinet right shell132 and the heat exchanger cabinet left shell 134. Assembly recesses 224may accept mounting hardware therein for joining the heat exchangercabinet 104 to the blower cabinet 102. In this embodiment, the recesses224 are substantially shaped as box shaped recesses, however, inalternative embodiments, the recesses 224 may be shaped any othersuitable manner. Additionally, one or more of the heat exchanger cabinetright shell 132 and the heat exchanger cabinet left shell 134 maycomprise integral fastener retainer protrusions 226. Fastener retainerprotrusions 226 may be used to hold threaded nuts or other fasteners.Further, in other embodiments, retainer protrusions 226 may themselvesbe threaded or otherwise configured to selectively retaining fastenersinserted therein. Still further, the heat exchanger cabinet right shell132 and the heat exchanger cabinet left shell 134 may comprise supportbar slots 228 configured to receive the opposing ends of a selectivelyremovable structural crossbar.

Referring now to FIGS. 4 and 6, one or more of the blower cabinet rightshell 136 and the blower cabinet left shell 138 may comprise blowerassembly mounting channels 230 bound above and below by blower assemblyrails 232. The blower assembly rails 232 protrude inwardly from theremainder of the respective interior side surfaces 154 so thatcomplementary shaped structures of the blower assembly 130 may bereceived within the channels 230 and retained within the channels 230 bythe blower assembly rails 232. In this embodiment, the blower assembly130 may be selectively inserted into the blower cabinet 102 by aligningthe blower assembly 130 properly with the blower assembly mountingchannels 230 and sliding the blower assembly 130 toward the AHU backside 112. Of course, the blower assembly 130 may be selectively removedfrom the blower cabinet 102 by sliding the blower assembly 130 away fromthe AHU back side 112.

It will further be appreciated that one or more of the blower cabinetright shell 136 and the blower cabinet left shell 138 may comprisefilter mounting channels 234 bound above and below by filter rails 236.The filter rails 236 protrude inwardly from the remainder of therespective interior side surfaces 154 so that complementary shapedstructures of a filter may be received within the channels 234 andretained within the channels 234 by the filter rails 236. In thisembodiment, a filter may be selectively inserted into the blower cabinet102 by aligning the filter properly with the filter mounting channels234 and sliding the filter toward the AHU back side 112. Of course, thefilter may be selectively removed from the blower cabinet 102 by slidingthe filter away from the AHU back side 112. In some embodiments, thefilter mounting channel 234 may be sloped downward from the front to theback of the AHU 100. Further, in some embodiments, one or more of thefilter rails 236 may comprise filter protrusions 238 which may serve tomore tightly hold a filter inserted into the filter mounting channels234. In some embodiments, one or more of the blower cabinet right shell136 and the blower cabinet left shell 138 may comprise fastener retainerprotrusions 226. Still further, one or more of the blower cabinet rightshell 136 and the blower cabinet left shell 138 may comprise integralassembly recesses 240. Assembly recesses 240 may be located near anupper end of the blower cabinet right shell 136 and the blower cabinetleft shell 138. Assembly recesses 240 may accept mounting hardwaretherein for joining the blower cabinet 102 to the heat exchanger cabinet104. In this embodiment, the recesses 240 are substantially shaped asbox shaped recesses, however, in alternative embodiments, the recesses240 may be shaped in any other suitable manner.

Referring now to FIGS. 7 and 8, oblique front and rear views of panel124 are shown, respectively. In this embodiment, the outer skin 125 maycomprise the foamed and/or unfoamed polymeric material that meets UL723and/or ASTM E84 of at least 25/50 or better and/or maintains or exceedsa minimum insulation value for a given application, in some cases, an RValue of about 4.2 or greater, such as, but not limited to,polyetherimide, while a concavity of the outer skin 125 that isgenerally open toward a rear direction may be at least partially filledthe foamed and/or unfoamed polymeric material that meets UL723 and/orASTM E84 of at least 25/50 or better and/or maintains or exceeds aminimum insulation value for a given application, in some cases, an RValue of about 4.2 or greater, such as, but not limited to,polyetherimide, to form a structural and/or insulative and/or fire/smokeresistant structure 127 that is generally represented in FIG. 8 bydashed lines along at least the most rearward edges of the structure127. In some cases, the outer skin 125 and the structure 127 may beintegrally formed so that the panel 124 comprises a substantiallyunitary construction.

While many of the features of the heat exchanger cabinet right shell132, heat exchanger cabinet left shell 134, blower cabinet right shell136, blower cabinet left shell 138, and/or panels 120,124 may be formedintegrally to those respective components in a single molding and/orinjection process. However in alternative embodiments, the variousintegral features may be provided through a series of moldings, and/orinjections, thermal welding, gluing, or any other suitable means ofassembling a singular structure comprising the various features as iswell known to those skilled in the art. Further, one or more of thecomponents disclosed herein as being formed integrally, in someembodiments, may be formed from multiple components coupled together.

Referring now to FIGS. 9 and 10, an oblique front and an orthogonal rearview of an alternative embodiment of a panel 300 are shown,respectively. The panel 300 is substantially similar to panel 124 butdiffers in that the panel is integrally formed of foamed and/or unfoamedpolymeric material that meets UL723 and/or ASTM E84 of at least 25/50 orbetter and/or maintains an insulation value R Value of about 4.2 orgreater, such as, but not limited to, polyetherimide. In thisembodiment, the panel 300 further comprises a gasket 302 that extendsalong a perimeter of the rear wall of the panel 300. In some cases, thepanel 300 may be utilized to seal an AHU such as AHU 100 and/or anyother HVAC cabinet and/or duct configured to pass air therethrough.

While many of the features of the heat exchanger cabinet right shell132, heat exchanger cabinet left shell 134, blower cabinet right shell136, blower cabinet left shell 138, and/or panels 120,124 may be formedintegrally to those respective components in a single molding and/orinjection process. However in alternative embodiments, the variousintegral features may be provided through a series of moldings, and/orinjections, thermal welding, gluing, or any other suitable means ofassembling a singular structure comprising the various features as iswell known to those skilled in the art. Further, one or more of thecomponents disclosed herein as being formed integrally, in someembodiments, may be formed from multiple components coupled together.

Referring now to FIG. 11, an oblique front cut-away view of a furnaceaccording to an embodiment of the disclosure is shown. Furnace 400comprises a modulating combustion system 414. It will be appreciatedthat the term, “modulating,” as used in this disclosure is meant toindicate that a system or device may be selectively operated atsubstantially any value over a range of performance values in a mannerconsistent with a control resolution of the system. Generally, thefurnace 400 is operable so that the furnace 400 may selectively performat substantially any selected output capacity value (kBtu/Hr) rangingfrom a maximum output capacity (100% output capacity) to a minimumoutput capacity (e.g., in some embodiments, about 40% of the maximumoutput capacity) with the modulating combustion system 414 capable ofbeing constantly operated over a range of output capacities. Themodulating combustion system 414 is housed within the cabinet 412 andcomprises a burner assembly 416, a modulating gas valve assembly 418,and a control assembly 420. The furnace 400 further comprises a heatexchanger assembly 422 which comprises a plurality of heat exchangers424, a variable speed induced draft blower 426, and a variable speedcirculating air blower 428. It will be appreciated that the furnace 400further comprises a combustion intake space 430 that surrounds theexterior of the draft blower 426 and the exterior of the heat exchangers424. When the draft blower 426 draft is operated, air is drawn from theintake space 430 and is passed through the heat exchangers 424 and intoa header 434 that accepts exhaust from the heat exchangers 424 andprovides a flow path for the exhaust to reach the draft blower 426. Itwill be appreciated that during operation of the furnace 400, the localpressure within the intake space 430 may be different from the localpressure within the header 434. In this embodiment, any of thecomponents of the cabinet 412 and/or the exhaust 432 may comprise foamedand/or unfoamed polymeric material that meets UL723 and/or ASTM E84 ofat least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide. Insome cases, the furnace 400 may comprise a panel substantially similarto panel 124 and/or panel 300.

Referring now to FIG. 12, a simplified schematic diagram of the aircirculation paths for a structure 500 conditioned by two HVAC systems501 is shown. In this embodiment, the structure 500 is conceptualized ascomprising a lower floor 502 and an upper floor 504. The lower floor 502comprises zones 506, 508, and 510 while the upper floor 504 compriseszones 512, 514, and 516. The HVAC system 501 associated with the lowerfloor 502 is configured to circulate and/or condition air of lower zones506, 508, and 510 while the HVAC system 501 associated with the upperfloor 504 is configured to circulate and/or condition air of upper zones512, 514, and 516. In addition to the components of HVAC system 501described above, in this embodiment, each HVAC system 501 furthercomprises a ventilator, a prefilter, a humidifier, and a bypass duct.The ventilator may be operated to selectively exhaust circulating air tothe environment and/or introduce environmental air into the circulatingair. The prefilter may generally comprise a filter media selected tocatch and/or retain relatively large particulate matter prior to airexiting the prefilter and entering the air cleaner. The humidifier maybe operated to adjust a humidity of the circulating air. The bypass ductmay be utilized to regulate air pressures within the ducts that form thecirculating air flow paths. In some embodiments, air flow through thebypass duct may be regulated by a bypass damper while air flow deliveredto the zones 506, 508, 510, 512, 514, and 516 may be regulated by zonedampers. Still further, each HVAC system 501 may further comprise a zonethermostat and a zone sensor. In some embodiments, a zone thermostat maycommunicate with the system controller and may allow a user to control atemperature, humidity, and/or other environmental setting for the zonein which the zone thermostat is located. Further, the zone thermostatmay communicate with the system controller to provide temperature,humidity, and/or other environmental feedback regarding the zone inwhich the zone thermostat is located. In some embodiments, a zone sensormay communicate with the system controller to provide temperature,humidity, and/or other environmental feedback regarding the zone inwhich the zone sensor is located. While HVAC systems 501 are shown as aso-called split system comprising an indoor unit located separately fromthe outdoor unit, alternative embodiments of an HVAC system 501 maycomprise a so-called package system in which one or more of thecomponents of the indoor unit and one or more of the components of theoutdoor unit are carried together in a common housing or package. TheHVAC system 501 is shown as a so-called ducted system where the indoorunit is located remote from the conditioned zones, thereby requiring airducts to route the circulating air. However, in alternative embodiments,an HVAC system 501 may be configured as a non-ducted system in which theindoor unit and/or multiple indoor units associated with an outdoor unitis located substantially in the space and/or zone to be conditioned bythe respective indoor units, thereby not requiring air ducts to routethe air conditioned by the indoor units. Still referring to FIG. 12, thesystem controllers may be configured for bidirectional communicationwith each other and may further be configured so that a user may, usingany of the system controllers, monitor and/or control any of the HVACsystem 501 components regardless of which zones the components may beassociated. Further, each system controller, each zone thermostat, andeach zone sensor may comprise a humidity sensor. As such, it will beappreciated that structure 500 is equipped with a plurality of humiditysensors in a plurality of different locations. In some embodiments, auser may effectively select which of the plurality of humidity sensorsis used to control operation of one or more of the HVAC systems 501.This disclosure contemplates that any of the components of FIG. 12 thatreceive airflow therethrough, whether a duct, cabinet, and/or any othertype of air delivery pipe, tube, and/or passage, may comprise foamedand/or unfoamed polymeric material that meets UL723 and/or ASTM E84 ofat least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide.

FIGS. 13-15 are orthogonal side views of panels comprising hooks. Thepanel 600 of FIG. 13 comprises a hook 602 that is mechanically attachedto the remainder of the panel 600 via an adhesive and/or a fastener. Thepanel 700 of FIG. 14 comprises a hook 702 that is integrally formed witha skin 704 of the panel 700. The panel 800 of FIG. 15 comprises a hook802 that is integrally formed with the remainder of the panel 800. Anyof the portions and/or components of the panels 600, 700, 800 maycomprise foamed and/or unfoamed polymeric material that meets UL723and/or ASTM E84 of at least 25/50 or better and/or maintains or exceedsa minimum insulation value for a given application, in some cases, an RValue of about 4.2 or greater, such as, but not limited to,polyetherimide.

In some embodiments, panels and/or AHU components constructed of foamedand/or unfoamed polymeric material that meets UL723 and/or ASTM E84 ofat least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide, mayprovide acceptable flatness, rigidity, and/or insulative properties toprevent condensation while also resisting burning and/or charring of thecomponents. In some cases, the panels and/or AHU components may, withoutsubstantial further processing provide acceptable aesthetic qualities,such as a desirable smoothness and/or glossiness.

In some cases, panels and/or AHU components constructed of foamed and/orunfoamed polymeric material that meets UL723 and/or ASTM E84 of at least25/50 or better and/or maintains or exceeds a minimum insulation valuefor a given application, in some cases, an R Value of about 4.2 orgreater, such as, but not limited to, polyetherimide, may be constructedby die cutting the material to complement skin shapes and then vacuumforming or pressure forming plastic skin sheets on as many as five sidesof the die cut material followed by cutting the skinned sheet out inline of a thermoform machine. The thermoform machine may receivegenerally rectangular shapes and then punch out shapes and holes afterthermoforming. Sheets may be extruded to match colors and cut to meetshape requirements. In some embodiments, some components may be die cutand thereafter pressure-formed to produce contoured surfaces. In somecases, sheets and/or skins may be coextruded with components formed offoamed and/or unfoamed polymeric material that meets UL723 and/or ASTME84 of at least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide, sothat dissimilar materials are simultaneously extruded. Foamed componentsmay be joined to other components by vertically dropping like a parisonand/or by gluing the foamed components to the other components. Thecomponents comprising foamed and/or unfoamed polymeric material thatmeets UL723 and/or ASTM E84 of at least 25/50 or better and/or maintainsor exceeds a minimum insulation value for a given application, in somecases, an R Value of about 4.2 or greater, such as, but not limited to,polyetherimide, may be caste into shapes, coextruded withreinforcements, and/or provided aesthetically pleasing skinned surfacesusing heat, pressure, and/or chemicals. In some cases, injectionmolding, two shot molding for foam portions and skin portions, andinsert molding the foam portions are contemplated.

In some cases, panels, doors, and/or other removable barriers comprisingfoamed and/or unfoamed polymeric material that meets UL723 and/or ASTME84 of at least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide, maybe attached to other components by sandwiching a bracket betweenthermoformed skin and the foam, mechanically and/or chemically fasteningthe foam to the other component, using screws and/or other fasteners tojoin the component to other components, using magnetic strips, gluingand/or adhesion mounting, providing the component with a featurecomplementary to a feature of the other component to which it is joined,and/or by packing or subsequently sealing the barriers to the othercomponents. Panels, doors, and/or other removable barriers comprisingfoamed and/or unfoamed polymeric material that meets UL723 and/or ASTME84 of at least 25/50 or better and/or maintains or exceeds a minimuminsulation value for a given application, in some cases, an R Value ofabout 4.2 or greater, such as, but not limited to, polyetherimide, maybe provided with seals using exiting seal bead equipment, forming flushmounting surfaces in the components, using a peel and stick gasketmaterial, using rib or other types of features to create hard seals onrecesses of the components, using wiper style gasket material to seal ina frame so that internal pressures assist in maintaining the seal, usingextruded rubber tubes seals such as those used in automotiveapplications, and/or the like. Seal attachments may be accomplished byutilizing insert mold seals, coextruding the seals with othercomponents, gluing the seals to the panels, doors, and/or otherremovable barriers, using adhesive tape to attach the seals,ultrasonically welding the seals in place, heat staking the seals inplace, and/or otherwise mechanically fastening the seals in place. Itwill further be appreciated that this disclosure contemplatesretrofitting exiting cabinets that initially comprise foil facedfiberglass with panels, doors, and/or other removable barrierscomprising foamed and/or unfoamed polymeric material that meets UL723and/or ASTM E84 of at least 25/50 or better and/or maintains or exceedsa minimum insulation value for a given application, in some cases, an RValue of about 4.2 or greater, such as, but not limited to,polyetherimide. In some cases, components comprising foamed and/orunfoamed polymeric material that meets UL723 and/or ASTM E84 of at least25/50 or better and/or maintains or exceeds a minimum insulation valuefor a given application, in some cases, an R Value of about 4.2 orgreater, such as, but not limited to, polyetherimide, may be pressureformed onto a side of a preexisting wall that is exposed to airflow sothat HVAC system noise is reduced.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, Rl, and an upper limit,Ru, is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable rangingfrom 1 percent to 100 percent with a 1 percent increment, i.e., k is 1percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent,51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98percent, 99 percent, or 100 percent. Moreover, any numerical rangedefined by two R numbers as defined in the above is also specificallydisclosed. Use of the term “optionally” with respect to any element of aclaim means that the element is required, or alternatively, the elementis not required, both alternatives being within the scope of the claim.Use of broader terms such as comprises, includes, and having should beunderstood to provide support for narrower terms such as consisting of,consisting essentially of, and comprised substantially of. Accordingly,the scope of protection is not limited by the description set out abovebut is defined by the claims that follow, that scope including allequivalents of the subject matter of the claims. Each and every claim isincorporated as further disclosure into the specification and the claimsare embodiment(s) of the present invention.

What is claimed is:
 1. An HVAC airflow duct, comprising: a polymericmaterial that meets UL723 and/or ASTM E84 of at least 25/50 or betterand/or maintains or exceeds a minimum insulation value.
 2. The HVACairflow duct of claim 1, wherein the polymeric material is a foamedmaterial.
 3. The HVAC airflow duct of claim 1, wherein the polymericmaterial is an unfoamed material.
 4. The HVAC airflow duct of claim 1,wherein the polymeric material comprises polyetherimide.
 5. The HVACairflow duct of claim 1, wherein the duct comprises a removable panel.6. The HVAC airflow duct of claim 5, wherein the removable panelcomprises the polymeric material that meets UL723 and/or ASTM E84 of atleast 25/50 or better and/or maintains or exceeds a minimum insulationvalue.
 7. The HVAC airflow duct of claim 5, wherein the removable panelcomprises polyetherimide.
 8. The HVAC airflow duct of claim 7, whereinthe polyetherimide is foamed.
 9. The HVAC airflow duct of claim 7,wherein the polyetherimide is unfoamed.
 10. The HVAC airflow duct ofclaim 7, wherein the panel comprises a hook.
 11. The HVAC airflow ductof claim 10, wherein the hook comprises polyetherimide.
 12. The HVACairflow duct of claim 11, wherein the hook is integrally formed with theremainder of the panel.
 13. An HVAC cabinet, comprising: an airflowpassage at least partially defined by a component comprising a polymericmaterial that meets UL723 and/or ASTM E84 of at least 25/50 or and/ormaintains or exceeds a minimum insulation value.
 14. The HVAC cabinet ofclaim 13, wherein the component is a composite component comprising askin joined to the component.
 15. The HVAC cabinet of claim 13, whereinthe component is a removable panel.
 16. The HVAC cabinet of claim 15,further comprising: a seal carried by the removable panel.
 17. The HVACcabinet of claim 15, further comprising: a panel mounting featurecarried by the removable panel.
 18. The HVAC cabinet of claim 17,wherein the panel mounting feature comprises a hook.
 19. The HVACcabinet of claim 17, wherein the panel mounting feature comprises thepolymeric material that meets UL723 and/or ASTM E84 of at least 25/50 orbetter and/or maintains or exceeds a minimum insulation value.
 20. TheHVAC cabinet of claim 13, wherein the cabinet further comprises at leastone of a furnace cabinet and an evaporator cabinet.